The overall goal of the Molecular Biology Core of this Alcohol Research Center is to support studies that pursue the genes underlying alcohol- seeking behavior, alcoholism, and related diseases. The Core has developed polymerase chain reaction (PCR) - based genotyping assays for the alcohol metabolizing enzymes ADH2, ADH3, ALDH2, and CYP2El and has determined the allele frequencies of these loci in various ethnic populations. We will continue to offer these genotyping services to investigators in order to determine if there are further relationships between these enzymes and responses to alcohol. The Core will also employ single strand length polymorphism and cycle sequencing assays to search for polymorphisms in the promoters of ADH1, ADH2, ADH3, ADH4, ADH7, ALDH1 and ALDH2. If a difference is found, we will develop a PCR-based genotyping assay. To complement our human studies, a new focus of the Molecular Biology Core will be the support of QTL mapping studies in animal lines selected for alcohol drinking. The rat studies will be expedited by performing marker heterozygosity screening in the N/Nih rats. Subsequent screening of the high (HARF) and low (LARF) drinking rats from the Addiction Research Foundation (ARF) are proposed for years 3 and later. The high (HAP1) and low (LAP1) alcohol preference mice, bred by the Mouse Selective Breeding Component, will be tested with markers in candidate regions identified in the recombinant inbred mice as possible locations for QTLs underlying alcohol preference.